This invention relates to detection of gastrointestinal conditions. More particularly, this invention relates to gastrointestinal screening that can be carried out by persons lacking medical training, such as by ordinary patients, to determine whether gastrointestinal conditions exist that warrant further investigation by trained medical personnel.
Many technologies exist for obtaining information regarding a person's gastrointestinal tract using an instrument disposed within the person's gastrointestinal tract. For instance, endoscopy may be performed to enable a medically trained person to examine a patient's gastrointestinal tract visually for conditions of interest such as cancerous or pre-cancerous tissues, bleeding, or infection. The American Cancer Society recommends that anyone over the age of fifty undergo routine colonoscopy for the screening of colorectal cancer every ten years, or flexible sigmoidoscopy every five years. There may be no other indication for these procedures.
Colonoscopy and sigmoidoscopy have drawbacks and limitations. They are relatively costly, requiring appropriate patient preparation and the time of a doctor to perform them. They are often regarded as uncomfortable and embarrassing. They may require some level of anaesthesia, which has associated risks. Additional risks such as bowel perforation are associated with the procedures themselves. They are performed in a doctor's office or hospital, which lacks privacy and convenience. They do not reach the small intestine, where inflammation, bleeding, and cancer can occur.
To address some of the drawbacks and limitations of colonoscopy and sigmoidoscopy, so-called “capsule endoscopes” have been developed. These are self-contained devices that are small enough to pass through the gastrointestinal tract, and contain apparatus to acquire image data for diagnostic purposes as they do so. For example, Given Imaging Ltd. of Yoqneam, Israel markets a device under the trademark “PillCam” that can be swallowed; as it passes through the digestive system, it acquires video images and transmits video data to a data recorder worn by the patient for storage and later review by a physician for diagnosis. Such capsules are, at present, fairly expensive single-use devices. Interpretation of the recorded capsule endoscopy data by a physician may require on the order of an hour.
Various self-contained diagnostic data acquisition devices that can be swallowed and pass through the gastrointestinal tract are disclosed in U.S. Pat. No. 6,240,312 to Alfano et al. and in U.S. Patent Application Publication US2001/0051766A1 to Gazdzinski. Such devices are intended to enable a physician to make a diagnosis, and require a medically trained person to review the acquired data for that purpose.
Screening tests may be used to help determine which patients should receive diagnostic procedures. Desirable properties of such a screening test typically include a cost that is lower than the cost of the diagnostic procedure being screened for, and the ability to be administered by someone without the medical training required for the diagnostic procedure being screened for, particularly by the patient being screened. For instance, as a screening test to help determine if a colonoscopy or sigmoidoscopy should be performed, a patient can perform a Fecal Occult Blood Test (FOBT) or Fecal Immunochemical Test (FIT) to analyze the patient's stool for the presence of blood. Such blood-in-stool tests are relatively inexpensive and do not require a medically trained person, but they have drawbacks. For instance, some gastrointestinal conditions of interest, such as certain tumors, do not cause blood in the stool. Other conditions for which diagnostic tests need not be performed, such as hemorrhoids, may cause blood in the stool that results in a positive FOBT or FIT. Although a FOBT or FIT may indicate the presence of blood, it does not indicate the location in the gastrointestinal tract of the blood source. FOBT and FIT generally have poor sensitivity and specificity.
Screening the population with a simple procedure that can be performed privately outside the doctor's office could reduce the number of sigmoidoscopy and colonoscopy procedures performed, and provide significant savings to the healthcare system. It would be desirable to have a gastrointestinal screening test that is relatively inexpensive, that can be administered by a person without medical training, such as a patient, and that provides an output that correlates well with the appropriateness of diagnostic testing. The present invention provides electronic capsules for gastrointestinal screening, and methods of gastrointestinal screening using such electronic capsules.
Gastrointestinal screening in accordance with the present invention includes disposing a self-contained electronic capsule in a gastrointestinal tract. Embodiments of the invention include an electronic capsule that is adapted to acquire data that is responsive to one or more physical conditions in the gastrointestinal tract and to compare the acquired data with stored threshold data in order to generate a discrete output relating to the condition of the gastrointestinal tract. Other features and aspects of the present invention may be understood with reference to the following description, the claims, and the drawing.